A PHOTO posted on Twitter that may have exposed the new identity of James Bulger’s killer Jon Venables is being investigated by the UK Attorney General’s office.

Venables and Robert Thompson, who brutally murdered the toddler 20 years ago this week in Liverpool when they were just ten years old, are protected by an injunction granting them lifelong anonymity for fear of vigilante revenge attacks.

But a photograph purporting to show Venables smiling and unshaven at a birthday party was uploaded on to Twitter on Tuesday.

More than 100 Twitter followers re-tweeted the image. Some comments on the page, which have now been deleted, suggested he would be lynched by vigilante mobs on his release from prison.

It prompted an investigation by the Attorney General’s Office, together with police, prison authorities and the Ministry of Justice.

A spokesman refused to confirm or deny whether the picture was Venables.

The killers were jailed for life for James’s murder in 1993 but released on licence with new identities in 2001.

But Venables is now behind bars again. His parole was revoked in 2010 and he was jailed for two years after admitting downloading and distributing images of children.

He has applied for release but James’s mother Denise Fergus hopes to address his parole hearing, arguing he is a psychopath who remains a danger to society.

A spokesman for the Attorney General’s Office said: “The Attorney General’s Office has been alerted to a possible contempt of court. We are liaising with the Ministry of Justice and others to establish the facts.

“We can neither confirm nor deny whether the pictures in question are of Jon Venables.

“It should be noted, there is a worldwide injunction in place which prevents the publication of any images or information purporting to identify anyone as Jon Venables.”